On Sunday morning, my grandfather and I went to the pharmacy in the lotus pond and bought two boxes of pills-two boxes of Weiershu, one box of 44 yuan and one box of 22 yuan. Grandpa gave her 50 yuan, and the clerk gave it to Grandpa 6 yuan. After I found the change, I calculated it with decimal addition and subtraction. Grandpa can also pay like this: 1. Give it to 40 yuan, the shop assistant, and then pay 5 yuan. The asking price is 1 yuan. 2. If Grandpa has change, he can pay 40 yuan first and then 4 yuan.